Staple



Patented Jan. 26, 1943 Irvin Maxwell Reid and Charles H. Johnson, EastJaffrey, N. H., assignors to United Shoe Machinery Corporation,.Flemington, N. J., a corporation of New Jersey Application March 31,1941, Serial No. 386,055

3 Claims.

This invention relates to fastening members for use in securingmaterials together and more particularly to staples adapted for use insecuring materials to walls.

Ordinary staples, while used for this general type of work for manyyears, have been found not particularly satisfactory for the workbecause of their lack of holding power and also because their thick,narrow bar portions not only do not cover much of the material operatedupon but, when driven fiush with the work, have a tendency to, and oftendo, out through the layers or sheets of material operated upon with theresult that the sheet material is damaged and the staple is rencleredineffective as a fastening.

An important object of the present invention is to provide an improvedfastening member or staple of novel construction which will obviate thedifiiculties refer-red to above in connection with the use of ordinarystaples, and which will be particularly well adapted for use in securingsheet materials to walls even when the Walls are "composed of relativelysoft, fragile or readily breakable material.

In some parts of the country, particularly in the southern andsouthwestern sections Where the climate is warm and where the extremesin humidity and. dryness are experienced during the year, the interiorwalls and ceilings of dwelling houses and other buildings are formed inmany instances of a manufactured wall board product known as gypsumboard or plaster board. These manufactured wall boards, as is wellknown, are composed of outside layers of relatively thick cardboardspaced apart about one-half inch, the space therebetween being filledwith some kind of plaster such as gypsum or similar material. In orderto apply wallpaper to walls composed of such materials the walls arefirst covered with a lightweight fabric known as decorators canvas andthe wallpaper is then pasted to this canvas which proxides a flexiblebase for the paper and tends to prevent it from cracking or splitting.The canvas is attached to the gypsum or plaster board walls by drivenfastenings, such as tacks, staples and so forth which are usually drivenby hand with a hammer or other driving tool.

When single shank fiat headed tacks are used in this work the workmenuse a magnetic hammer, that is, a hammer having a magnetized head whichattracts or pulls the flat head of the tack against the driving face ofthe hammer and holds it there with the shank of the tack projectingoutwardly in position to be driven. The tack is then driven flush withthe surface vof the work by a s5 single blow of the hammer, thus makingthe operationquiek and easy to execute for those skilled in the trade.It has been found, however, that single shank tacks are not satisfactoryfor this work because they have very little holding power in gypsum orplaster board and when driven they disrupt or break up the relativelysoft or fragile structure of the gypsum material forming the wall board.

Moreover, ordinary U-shaped staples having the usual thick, narrowcrossbar and depending legs are entirely unsatisfactory for this workbecause they have insufficient holding power in this gypsum board andsimilar materials and because they likewise disrupt the structure of thegypsum board. In addition, ordinary staples cannot be used with amagnetized hammer because they have no flat head or driving surface liketacks to be attracted and held against the magnetized head of the hammerso that the legs of the staple will project outwardly in position to bedriven. Furthermore, it is impractical to attempt to use ordinarystaples by positioning and holding them in position with the fingersuntil driven. While special types of staples have been used heretoforein this work, their use has always required the provision of specialtools or equipment, such as automatic hammers or similar tools, whichinvolves considerable expense more particularly when it is realized thatsuch tools can generally be of use only for the single purpose intended.What is of equal importance in this line of work, moreover, is the factthat the special equipment necessary for use with these special types ofstaples calls fora radical change in the long established method ortechnique of the workmen in'applying the canvas to the gypsum boardwalls because th workmen have long been accustomed to use a magnetizedhammer and have become skilled in its use so thatany attempt to changethis usual procedure upsets the long-established practice of the workmenand has a tendency to disrupt or create disturbances in the trade.

To this end the invention provides, in accordance with one feature, animproved fastening member or staple comprising a bar portion and a pairof relatively thick, rigid legs depending therefrom, the legs converginginwardly toward each other a relatively small amount. The bar .portionof the staple is of substantially greater width than the legs and it ismuch thinner in cross section than said legs up to its point of unionwith the legs so that the connections it provides with the legs are ofsubstantially greater flexibility than ,enyother portion of the staple,thereby permitting the legs to converge in the work piece until theirends substantially meet in the material into which the staple isinserted, thereby locking the staple in the material and greatlyincreasing its holding power and resistance to withdrawal.

As herein illustrated, the legs of the staple initially convergeinwardly toward each other only a small amount and the thin flexibleconnections with the bar portion permits further converging of the legswhen the staple is driven. Moreover, this converging action takes placewithout damaging the material into which the staple is driven as, forexample, in the case of plaster board, by breaking up or crumbling suchmaterial.

As illustrated, the wide bar portion of the staple enables it to engagea relatively large area of the material to be fastened, prevents the barportion from cutting through the material when the staple is driven, andalso renders the connections with the legs sufficiently inflexibletransversely of the bar portion to prevent lateral deflection of thelegs during their converging action. The .bar portion of the staple, asherein illustrated, is also substantially flat in cross section so thatit will provide the staple with a good driving surface or headparticularly adapted for use, for example, with the so-called magnetichammer, that is, one having a magnetized head or driving surfaceespecially convenient for use in the type of work referred to. Theextreme thinness of the .bar portion, besides rendering the connectionswith the legs relatively yielding or flexible, also permits the barportion to be driven substantially flush with the surface of thematerials being fastened, as for example, where canvas is being securedto wall board such as gypsum or plaster board. As herein illustrated,the thin, fiat bar portion of the staple is preferably oval in shape orperiphery which provides relatively large surfaces for engaging thematerial fastened and for co-operating with the hammer or other drivingtool.

With the above and other objects and features in view, the inventionwill now be described with reference to the accompanying drawing andwill thereafter be pointed out in the claims.

In the drawing,

Fig. 1 is a greatly enlarged perspective view of one side of thefastening member or staple forming the subject-matter of the invention;

Fig. 2 is an elevation of the opposite side of the staple;

Fig. 3 is a plan view of the staple;

Fig. 4 is a side elevation partly in section showing the condition ofthe staple after it has been driven into materials to be fastenedthereby;

Fig. 5 is a side view similar to Fig. 4 but with a part of the barportion and a leg of the staple shown in cross section; and

Fig. 6 illustrates how the staple may be carried by a magnetized hammerfor insertion into the work.

The improved fastening member or staple I0 of the present invention isillustrated on a greatly enlarged scale in Figs. 1 to 3 of the drawingand, as shown in those figures, comprises a bar or body portion I2having a pair of legs or shanks M depending downwardly therefrom. Thelegs M depend from the opposite ends of the bar portion I2 and areprovided at their lower ends with piercing points l6 produced byinclined diagonal cuts I! which extend considerable distances upwardlyfrom the ends of the legs. Beyond or above the points Hi, the legs M aresubstantially rectangularin shape and, as shown in the drawing, arerelatively thick in cross section as compared with the bar portion l2 ofthe staple. Moreover, although the legs are practically straightthroughout their lengths, they are arranged initially to incline orconverge inwardly toward each other a relatively small amount, as shownin Figs. 1 and 2, the angles between the bar portion and the legs beingslightly acute.

The inclined cuts or bevels [1 which produce the points IE on the staplelegs I 4 are located at opposite sides of the legs with respect to eachother or, in other words, the inclined cut on one leg is on the forwardside of such leg when the bar portion I2 is positioned crosswise, asshown in Figs. 1 and 2, and the inclined cut on the opposite leg is onthe rear side of the leg, the points l6 of the staple, however, beingsubstantially in line with each other crosswise of the staple, orlengthwise of its bar portion. Since the inclined cuts I! are notlocated on the outside surfaces of the legs or those most remote fromeach other, that is, the surfaces that form continuations of the topside of the bar portion l2, the surfaces I! have no tendency when thestaple is driven to cause the legs to converge inwardly or toward eachother a greater amount than their initial convergence. Moreover, it willbe observed that the sharp edges I 5 of the legs, which extend from thepoints It upwardly, are inclined at the same angles and are parallel toeach other so that these edges, which are produced by the inclined cutsI! passing diagonally through the legs, likewise have no tendency tocause the legs to converge or move together when the staple is driven.

The bar portion I2, which forms the driving head of the staple, issubstantially fiat in cross section and, in plan view (Fig. 3), itsperiphery is substantially oval in shape except at its opposite ends Hwhere the legs join the bar portion, which ends project outwardly fromthe bar portion. The bar portion I2 is also much greater in width thanthe legs l4 except where the legs join the bar portion, as is clearlyshown in Figs. 1 and 3. Moreover, this wide fiat bar portion or drivinghead I2 is extremely thin in cross section up to its point of union withthe legs l4 and these connections are thus rendered considerably moreflexible than any other portion of the staple so that they can bend orflex under a sufiicient blow without breaking.

In actual size, as shown approximately in Fig. 6, the legs of thestaple, above the pointed por tions [6, might be, for example,thirty-five to forty thousandths of an inch thick in cross section andthe bar portion by comparison might be ten or twelve thousandths thickheightwise of the staple. The angles upon which the legs M are inclinedinwardly with respect to the bar portion l2, as stated, are relativelyslight and, in the present instance, have been formed by bending thelegs inwardly until their points are about ,6 of an inch apart. Theforegoing dimensions, however, are merely illustrative of the relativeproportions of the staple and should not be regarded as limiting theinvention since the advantages thereof could be obtained with somewhatdifferent dimensions or proportions provided the features disclosedherein were also included.

As indicated above, the staple I 0 is adapted for use in securing layersof material together, as, for example, in securing a layer or sheet ofdecorators canvas to wall board material such as gypsum board which isused extensively in some localities for forming the interior walls andceilings of the rooms of houses. Accordingly, the staple has beenillustrated herein, by way of example, for this use. In Fig. 4 thestaple Iii is shown on an enlarged scale driven into a layer of gypsumboard IB to secure thereto a sheet of canvas 20, this gypsum board, asis well known, comprising spaced parallel outer layers 22 of strongfibrous material, such as heavy cardboard, between which is locatedplaster or similar material 2 1 which forms the commercial product.After the canvas is attached the wallpaper 23 may be applied in theusual manner by paste.

In this kind of work the staple is usually driven by a single blow of ahammer 26 which, as illustrated in Fig. 6, is preferably provided with ahead 28 the driving portion of which comprises a horse-shoe magnethaving two arms or poles 29, 3| which attract or pull the bar portion l2of the staple against the driving surfaces of these poles and hold thestaple in position to be driven with its bar portion spanning the polesof the magnet and its legs projecting outwardly there from. Obviouslythe wide fiat bar portion or driving head I? of the staple permits thismagnetized hammer to be used whereas, if the bar portion were the samewidth as the legs, as is the case with ordinary staples, a magnetizedhammer could not be used because the legs of such a staple would bepulled against the hammer as well as the bar portion and therefore wouldnot project outwardly in a position to be driven as they do in the caseof the large flat driving head l2, as illustrated in Fig. 6.

The staple iii is driven by the hammer 26 by a single blow. Asillustrated in Fig. 4, the thin flat bar portion l2 may be readilydriven so that its outer surface is substantially flush with the outersurface of the sheet of canvas 2! which is being attached to the gypsumboard I8. Moreover, the relatively large area engaged by the bar portion52 prevents it from cutting through the canvas or other material whichis being fastened.

As the staple is driven the legs Hi continue to converge while passinginto the material until their lower or pointed ends 16 substantiallymeet to form a triangular lock in the material, as shown in Figs. 4 and5, this result being obtained by reason of the initial inclination orconvergence of the legs I l and also because of the flexibility of theconnections of the legs with the thin driving head l2 which permits themto yield or bend under the force of the hammer blow in such a mannerthat the legs I4 will converge increasingly as they enter the material.

This increasing converging action of the legs of the staple upon beingdriven until they form a lock in the material may be further explainedas follows. The legs enter the material at points spaced apart from eachother a distance somewhat less than the width of the bar portion l2.Because of their slight initial inclination or convergence, the normaltendency of the legs would be to remain or continue on these slightangles as they pass into the material. However, as the upper portions ofthe legs, which extend gradually farther apart, descend into thematerial, these wider portions crowd or compact the material engagingtheir outer or remote sides and thus create a pressure against the legswhich increases progressively as the wider portions of the legs enterthe material, with a corresponding decreasing of pressure against theinner or adjacent surfaces of the legs.

Since the thin bar portion i2 is relatively flexible and the joints orconnections where the legs meet it can yield or bend a little, thisincreased pressure of the compressed material against the outsidesurfaces of the legs forces the legs to converge or toe inwardly moreand more as the legs pass into the material and this compressing actionincreases until, when the staple is fully driven and its bar portion isfiush with the surface of the material, the lower or pointed ends of thelegs have converged until they are substantially in engagement with eachother, thereby forming a mechanical lock which, it might be pointed out,is frictional as well as mechanical because of the pressure of thematerial against both sides of the legs.

Fig. 5 illustrates in cross section at 21 one end of the bar portionwhere a leg I4 joins it and it will be seen from that figure that therelatively thin connection or joint 2| between the leg and the barportion will permit such bending or flexing without distorting the flatdriving head. Fig. 4 illustrates also the manner in which the legs ofthe staple penetrate such material, for example, as gypsum or wall boardand increase their converging action while passing through the wallboard without damaging the material by breaking up its structure andcausing it to crumble. It will be clear from this figure, moreover, thatsince the ends of the legs Id practically meet in the material, theselegs form an eifective lock for holding the staple firmly in thematerial rather than relying upon friction alone for its holding power,as is the case with single shank tacks or ordinary staples the legs ofwhich are substantially perpendicular to the bar portion of the staple.Accordingly, the holding power of the present staple is greatlyincreased even in such relatively soft materials as plaster or gypsumboard and its resistance to withdrawal is likewise substantiallyincreased. If the frictional hold of the staple is impaired as timepasses, the mechanical lock remains to provide the holding power for thestaple.

Since the legs Id of the staple are relatively thick and strong, and areattached to the bar portion 12 by relatively wide though thin andflexible connections, as shown in Figs. 3 and 5, the attachment of thelegs to the bar portion is sufliciently strong to resist breakage fromcorrosion or other causes. The width of the thin, flexible connectionsof the legs with the bar portion also renders them sufficientlyinflexible transversely of the staple to prevent any lateral deflectionof the legs during their converging movement when driven. Moreover, asmentioned above, the wide fiat oval bar portion or head I2 provides asurface between the legs of the staple which will engage a relativelylarge area of the material to be fastened, in the present case, forexample, the sheet of canvas 29, thereby securing the canvas more firmlyto the gypsum board and reducing to a minimum the chances of the barportion cutting through the canvas when the staple is driven, assometimes happens in this work with ordinary staples having bar portionsof the same width or thickness as their legs. The outer or top surfaceof the oval bar portion, as stated, provides a large fiat driving headon the staple which may, of course, be used with an ordinary hammer butwhich, as illustrated in Fig. 6, is particularly well adapted for usewith a magnetized hammer with which ordinary staples could not be usedfor the reason pointed out above.

It will be understood that the novel staple of the present invention isnot limited to use in the particular kind of work illustrated herein orfor fastening together materials of the kind herein disclosed since thestaple could obviously be used with equally beneficial results andadvantages in other kinds of work or with other kinds of material.

Having thus described our invention, what We claim as new and desire tosecure by Letters Patent of the United States is:

1. A fastening member comprising a staple having a pair of relativelythick, rigid legs which are substantially straight but converge inwardlytoward each other a relatively small amount, said legs being flexiblyconnected together by a relatively wide, flat, oval-shaped bar portionwhich is much thinner than said legs up to its point of union with thelegs and is of suflicient size to cover a relatively large area, saidbar portion providing connections between said legs which are ofsubstantially greater flexibility than any other portion of the stapleand will thus permit the legs to converge readily toward each other wheninserted into a work piece without any tendency to fracture the materialof the work piece, but said connections being also sufficientlyinflexible transversely of the bar portion to prevent lateral deflectionof the legs during their converging movement.

2. A fastening member comprising a staple having a bar portion and apair of legs depending from the opposite ends thereof, said bar portionbeing relatively wide, flat and substantially oval in shape to cover arelatively large area, and said legs being relatively thick, rigid andinflexible and being substantially straight lengthwise but converginginwardly toward each other at relatively slight angles, said bar portionbeing much thinner than said legs up to its point of union with the legsand providing connections between the legs which have greaterflexibility than the other portions of the staple to permit the legsreadily to converge toward each other increasingly when inserted into awork piece without exerting sufiicient pressure against the work pieceto fracture the material thereof, said connections being alsosufficiently inflexible transversely of the bar portion due to thesubstantial width of said portion to prevent deflection of the legslaterally of the staple during their converging action, thereby causingthe legs to converge inwardly in the same plane widthwise of the staple,the initial convergence of said legs being such that when driven fullyinto the work piece they will be caused to converge suificiently towardeach other substantially to meet in said work piece to form a triangularlock therein.

3. A fastening member for use in relatively soft, breakable materialcomprising a staple having a bar portion and a pair of legs dependingtherefrom, said bar portion being wide, flat and substantially oval inshape to cover a relatively large area, and said legs being thick,straight and rigid enough to remain straight when driven into a workpiece, said legs initially converging inwardly toward each other arelatively small amount from the bar portion, said bar portion beingmuch thinner than said legs up to its point of union with the legs andthereby forming connections with said legs of such flexibility that thelegs will readily converge inwardly toward each other increasingly wheninserted into a work piece of relatively soft, breakable materialwithout any tendency to break or fracture said material, but saidconnections being also of such width transversely of the bar portion asto render them substantially less flexible in a transverse direction,thereby preventing the legs from being deflected laterally out of theirnormal plane during their converging movement so that the legs will becaused substantially to meet in said soft, breakable material by theirincreasing converging action to form a mechanical lock in the workpiece.

IRVIN MAXWELL REID. CHARLES H. JOHNSON.

